The invention relates to a method for assisting a person to plan a journey with an electric vehicle. The invention also includes an electrically drivable motor vehicle with a navigation device.
An electrically drivable motor vehicle, also referred to herein as an electric vehicle, may include a traction battery, referred to as accumulator for storing electrical energy, for operating an electric drive motor. Such traction battery may be permanently installed in the vehicle or designed as a replaceable module. Depending on the design, the traction battery must then be coupled to an electric power source for a certain period of time for charging at a charging station or the discharged traction battery must be replaced with a charged battery.
The route, which an electric vehicle with a fully charged traction battery can travel, is relatively short in relation to the route which a motor vehicle with an internal combustion engine and a full tank is able to travel. Accordingly, the travel must be carefully planned. Navigation devices for motor vehicles have the ability to provide information to an operator in response to a predetermined destination as to whether this destination can be reached with a current state of charge of the traction battery, or when this is not the case, where a charging station for charging the traction battery can be found along the planned route. One such method is relatively simple to implement, since starting from a current location of the vehicle and a given destination, a route can be automatically found on the basis of an appropriate optimization algorithm.
DE 195 19 107 C1 discloses a driving route advisory device for a motor vehicle which in order to reach a given destination, finds an optimal driving route by taking into consideration charging operations for the traction battery. This device has the disadvantage that the driver is forced to actually follow the driving route provided by the device, because he otherwise runs the risk that the vehicle becomes disabled before reaching another charging station.
EP 1 275 936 B1 discloses an information system for a vehicle which displays on a display screen a map, on which in addition to a recommended route to a given destination a detour region is presented, where the vehicle can detour from the recommended route without having to recharge energy until reaching the destination. However, with this information system, the driver must always set a target to find out which detour regions away from the route leading to the destination can still be approached.
If one wants to independently plan a journey and to find in relation to several contemplated driving routes, whether possibly a stopover for recharging the traction battery must be scheduled for these routes, then each of these driving routes must be entered into a navigation device and to note the charging stations specified by the navigation device. This circumstance can be particularly troublesome when several possible alternative routes are contemplated during a journey.